This invention relates generally to processor-based systems using semiconductor memory as their primary, non-volatile, re-programmable storage medium.
There is increasing interest in so called embedded processor-based systems. These systems often operate with reduced functionalities to provide desired performance at relatively low cost. In many cases, these embedded systems may be battery operated. Thus, their capabilities may be limited to improve battery lifetime.
For a variety of reasons including conserving battery life, reducing cost and providing a compact form factor, processor-based systems may be provided which do not use a hard disk drive as their non-volatile storage medium. In many processor-based system, a hard disk drive provides a convenient non-volatile storage medium that stores most of the information which the user desires to maintain permanently. This may include among other things, the operating system, application software, files and data, as examples. The information that is stored in the hard disk drive may be transferred for execution to system memory which conventionally is a volatile memory.
In many systems, hard disk drives provide a very high capacity, relatively quick storage medium. However, hard disk drives take more space and use more power than non-volatile semiconductor memories. In many embedded systems, re-programmable, non-volatile semiconductor memories are used as a primary storage system for processor-based systems. These semiconductor memories store the panoply of information normally stored in hard disk drives including operating systems.
In many cases, the semiconductor memories utilized as primary non-volatile storage media for processor-based systems are flash memories. These flash memories may be re-programmed without user intervention using well known on-board capabilities. These memories are generally accessed using row and column addresses. Thus, the memories are generally monolithic in that the location of files and other data in that memory is generally stored outside the memory.
Thus, there is a continuing need for a way to enable an operating system to store more information on a non-volatile re-programmable semiconductor memory and to access that information efficiently.